The following reference is believed to represent the state of the art:
U.S. patent application Ser. No. 13/160,535, METHODS, DEVICES, AND MEDIA FOR SECURE KEY MANAGEMENT IN A NON-SECURED, DISTRIBUTED, VIRTUALIZED ENVIRONMENT WITH APPLICATIONS TO CLOUD-COMPUTING SECURITY AND MANAGEMENT, by Gilad Parann-Nissany, filed Jun. 15, 2011.